Couldn't find if Apollo solves the database round trips issue with GraphQL (the joins/n+1 problem). Can anybody shed a light on it?

It's a lib working at a higher level so things like n+1 are left to be solved by the user since the implementation details depend very much on the underlying data storage.

If you use PostgreSQL however, i solve that problem :) https://subzero.cloud (GraphQL & REST api for your database) It's still in private beta but you can get a sense of how things are put together by looking a this OS project (just REST) https://github.com/subzerocloud/postgrest-starter-kit